A look at a new campaign which offers a guide to customers' legal rights when buying plants by post - plus, find out what else needs doing in the garden this week.

By Hannah Stephenson.

If you're among the unlucky people who order their plants by post and have received dead or dying plants, battered bulbs and dried-out specimens, help is at hand.

Which? Gardening, the Consumers' Association magazine, has just launched a 'Better Plants By Post' campaign to make people aware of their rights and encourage retailers to improve their services.

This followed a survey it carried out among customers who have bought plants online or by mail order/phone in the past two years.

Some 36% of respondents had experienced a problem when buying plants in this way, with the most common complaint being the quality of plants or bulbs provided, packages left on the doorstep while customers were away and damaged packaging.

Others received dead or dying plants, specimens that were too small or which quickly succumbed to disease and some which were rotten on arrival.

Only half of those who complained received replacements, while a fifth received a refund.

The survey also asked customers to rate the service they had received from 26 retailers.

David Austin Roses, Bloms Bulbs, Crocus and Sarah Raven came out top for customer satisfaction, while Garden Bargains, Spalding Bulbs and Bakker were at the bottom.

In its latest issue, the magazine offers tips on what you should do when faced with common problems and your legal rights.

If you receive a plant you think is dead, the Sale of Goods Act 1979 says that you are entitled to a refund as long as you have notified the retailer of the problem within 'a reasonable time'. What is reasonable depends on the circumstances, but is typically three to four weeks, or less, from when the goods are received. Contact the seller as soon as you know there's a problem.

Similarly, if a plant you receive is diseased, you can ask for your money back within a reasonable time, or a replacement. In the first six months, the onus is on the seller to prove the plants weren't supplied diseased rather than you having to prove that they were.

It makes no difference if the plants were damaged before they were sent or in transit, it's the seller's responsibility, so you can ask for your money back within a reasonable time, or a replacement. Don't let the seller put the onus on you to take it up with the courier they used.

If you're worried you haven't received the plant you ordered, but won't know until it flowers or fruits, you can ask for a refund (you could argue you have more than the usual 'reasonable time' as you couldn't know the problem until it flowers) or a replacement, sent at the seller's expense. Raise your concern with the seller as soon as you suspect they've sent you the wrong plant.

If you ordered a plant but by the time it was delivered the window for planting it or potting it up had passed and a specific date had been given for delivery, you could argue that time was of the essence in the contract and that by failing to deliver by that date, the seller breached the contract. You should get a refund.

If no specific delivery date was given, the seller should have delivered within a reasonable time. The reasonable time would depend on the circumstances and the window for planting the plant you ordered.

The campaign is urging retailers to adopt 10 key criteria - some legal obligations, others just good practice - to improve their service.

These include giving an accurate description of the plant (including its size) and flagging up any particular growing requirements, adopting strict quality control measures before the plants are sent out and ensuring packaging is secure enough to completely protect the plant in transit.

:: The full report is in the July/August edition of Which? Gardening. For more advice about buying plants by post, visit www.which.co.uk/plantsbypost. To try your first three issues of Which? and Which? Gardening for £3, call 0800 3898855, quoting VEG489F Best of the bunch - Delphinium They are among the most majestic of perennials in the cottage garden, throwing up towering spires in shades of blue, white, cream, lilac and pink varieties in mid-summer.

Delphiniums grow best in full sun or where they will receive sun for at least half the day. They like fertile, well-drained soil and won't survive the winter in waterlogged conditions, so make sure you dig in plenty of garden compost before planting to improve the soil's ability to hold water without waterlogging.

Most delphiniums need staking although some of the Elatum hybrids, such as 'Mighty Atom' and 'Lord Butler' have spires which will cope well in windy conditions.

Their best companions in a mixed border include dahlias, Japanese anemones and asters, although roses also make a stunning plant partner.

Make sure you protect the young plants from slugs in spring. Summer favourites include 'Faust', with its strong spikes of deep ultramarine, 'Loch Leven', which produces soft mid blue flowers with a white eye, and 'Cherub', a dainty pink-mauve variety which grows to between 55-165cm (22-66in) high.

Good enough to eat - Harvesting onions Those onions you planted earlier in the year should be ready for harvesting any time soon, but there are signs to show when they're ready for digging up.

They're ready when the leaves begin to turn yellow and flop. While some recommend that the leaves of onions be bent over to encourage them to ripen, it actually happens naturally anyway.

Ease the bulbs from the soil with a fork and leave them on the soil for a few days if it's warm and dry. To help them dry quicker for storage, make a chicken wire support for the bulbs, allowing air to circulate freely around them.

Once dry, onions can be either tied up to make an onion string which can then be hung in a shed, or just placed in a single layer in boxes.

Three ways to... Make the most of fertiliser 1. Don't overfeed your plant. Too much fertiliser inhibits the plant's uptake of water and plant foods from the soil, so follow the manufacturer's instructions carefully.

2. When planting large plants and shrubs, add a small handful of general fertiliser to the soil in and around the planting hole. Smaller plants won't need as much.

3. Remember that if you use a feed with a high ratio of nitrogen on a flowering or fruiting plant, the plant will make lots of soft leaf growth at the expense of flowers.

What to do this week :: Ensure your bird bath is filled up in dry weather.

:: Trim conifer hedges and take cuttings.

:: In warmer weather, pests and diseases can multiply rapidly. Greenfly and blackfly breed fast so keep on top of them and plant a variety of plants which will attract beneficial insects to keep a balance between pests and predators.

:: Introduce fish into your pond when the water is warmer.

:: Continue to mow and trim edges at least once a week.

:: Sow biennials, herbs and vegetables.

:: Plant autumn-flowering bulbs including Nerine bowdenii and colchicums.

:: In moist weather weed seedlings will appear almost overnight, so regular hoeing will deal with them.

:: Harvest seed from perennials on dry days and store dry, clean seed in small packages in a sealed box in a fridge.

:: Lift and divide spring-flowering bulbs. Many tulips and bedding hyacinths need to be lifted annually and stored, ready for re-planting in autumn.

:: Tie in new canes of blackberries and hybrid berries separately from the fruiting canes, so they don't blow about and damage the fruiting canes.